New shower (unequal water pressure)

[skb7]

I'm trying to install a Grohe 1000 Thermostatic mixer shower.

Now the dilemma I have is that the hot water in the bathroom comes from the Combi boiler (Bosch) via the mains whilst the cold feed from the storage tank on the roof, a good 30-35' in height. Will the shower struggle to offer a consistent temperature as these two pressures are different?

thanks for any help.

m[/i]

 

[Bamber gaspipe]

I'm trying to install a Grohe 1000 Thermostatic mixer shower.

Now the dilemma I have is that the hot water in the bathroom comes from the Combi boiler (Bosch) via the mains whilst the cold feed from the storage tank on the roof, a good 30-35' in height. Will the shower struggle to offer a consistent temperature as these two pressures are different?

thanks for any help.

m[/i]

Why is your bathroom supplied from a storage tank?

This used to be the case years ago when incoming mains pressure was poor, not so now.
You need to link your cold mains feeding your tank to the cold feed to your bathroom.

 

[skb7]

These apartments were built in the 60's. CW storage supplies all of the apartments in the block, we're on the ground floor.

When we moved in we had central heating installed, that's the way they did it.

You're right in what you say, i need to link the cold feed from the mains to the shower. I was hoping that I wouldn't have to do this though.

 

[Bamber gaspipe]

These apartments were built in the 60's. CW storage supplies all of the apartments in the block, we're on the ground floor.

When we moved in we had central heating installed, that's the way they did it.

You're right in what you say, i need to link the cold feed from the mains to the shower. I was hoping that I wouldn't have to do this though.

You didn`t say you were in an apartment ( you mean a flat don`t you, apartment is the name bestowed on a lowly flat to over inflate the market value ). You can put a pump on your cold water supply seeing as it is fed from a tank.

 

[skb7]

Without the pump it wouldn't work. Is that right? As it stands I couldn't use the mixer shower with two different water pressures/sources?

 

[skb7]

^bump^

 

[Breesey]

I would say it will work OK as is. You have a fair bit of head there. I replaced a thermostatic shower valve for someone the other day which is supplied exactly as you describe except that cold head was only about 8 feet. It works fine.

 

[skb7]

Brilliant, now I'll just have to convince the plumber I'll work. Think he's just trying to cover himself should it not work. Must have had four plumbers look at it so far and had for different answers.

 

[JPC]

last week i fitted a shower for a customer...usual hot gravity cold mains. advised him re unequal pressures and to try a venturi shower.
he did not like to look. we went down the route of a pressure equalising valve and it works fine (although not a very powerfull shower...but i did tell them!)

 

[skb7]

The plumber i had round is adamant it won't work and won't fit it. Grohe say it will, as long as the pressure of one isn't 5x more powerful than the other. The shop I got it from say it won't, someone tried to fit one to an un-balanced system and it didn't work.

It seems the only way I can be sure, and have the least hassle, is to fit a shower with separate hold and cold controls.

Bang goes me smart new Thermostatic shower.

Thanks anyways

 

[JPC]

what about the pressure equalising valve i just mentioned ?

http://www.plumbworld.co.uk/search?SearchString=pressure+equalising[url]

 

[skb7]

As you said the pressure wouldn't be very good.